1. This invention relates to a disk apparatus. More particularly, this invention relates to a disk apparatus comprising: at least one rotatable disk having at least one recording surface; at least one head for reading or writing information from or to said rotatable disk and head drive means for moving said head over said recording surface of the rotatable disk; and an enclosure for housing therein at least said rotatable disk, said head and said drive means.
2. Description of the Related Art
Recently, a highly sophisticated disk apparatus having a high recording capacity has been required in the related technical fields. However, due to the effort to attain such a high density, the head in the disk apparatus may be easily affected by external electrical noise.
Therefore, it is necessary to provide an electrical shielding means so that the disk apparatus operates without being affected by any external noise. In the prior art, a disk apparatus having an enclosure provided with a shielding means is known. For example, Japanese Unexamined Patent Publication (Kokai) No. 60-85796 discloses a disk apparatus having an enclosure which is covered by a shielding plate arranged between the enclosure and a printed circuit board. Japanese Unexamined Patent Publication (Kokai) No. 63-204508 discloses a magnetic head assembly of a disk apparatus providing with a shielding member for protecting electric elements on the printed circuit board. Japanese Unexamined Patent Publication (Kokai) No. 2-216897 discloses an shielded enclosure for housing therein electronic elements or apparatus. Japanese Unexamined Patent Publication (Kokai) No. 4-40691 discloses a disk apparatus including a housing made of resin and a shielding layer arranged on the inner surface of the housing.
Since the above-mentioned shielding member known in the prior art covers substantially the entire surface of the printed circuit board, the electrical shielding effects can be fully attained. However, the cost for the shielding member is high.
Unexamined Patent Publications (Kokai) No. 58-97161 and No. 3-23890 disclose a magnetic disk apparatus including a shielding means which is arranged so as to cover the moving region of the magnetic head. Also, Unexamined Patent Publication (Kokai) No. 3-14800 discloses a magnetic disk apparatus having a housing and a shielding means arranged on the inner surface of the housing so as to cover the area corresponding to the moving region of the magnetic head.
As the above-mentioned shielding member is arranged to cover only the moving region of the magnetic head, the cost for the shielding member can be reduced. However, the shielding member does not cover the printed circuit board and, therefore, the electrical elements, such as integrated circuits or the like, cannot be fully shielded, so that these electrical elements may be affected by external electrical noise.